Cardiovascular Safety Signals of Oral Versus Topical Minoxidil in FAERS: A Disproportionality Analysis (Analytic Cohort 2012–2025)

Oral minoxidil, including low-dose regimens, is increasingly used off-label for alopecia, but cardiovascular safety remains a clinical concern. We compared cardiovascular adverse event reporting patterns for oral versus topical minoxidil using a disproportionality analysis of the FDA Adverse Event Reporting System (FAERS). FAERS data (2004Q1-2025Q3) were imported and deduplicated; minoxidil reports were restricted to primary/secondary suspect (PS/SS) drugs and eligible reports from 2012 to 2025. Exposure was classified as ORAL, TOPICAL, BOTH, or UNKNOWN using a standardized route/dose-form dictionary. Signals for Core and Expanded cardiovascular MedDRA Preferred Terms (PTs) were assessed using reporting odds ratios (RORs) with 95% confidence intervals; sensitivity analyses included alopecia-restricted cohorts excluding hypertension indications. In the primary ORAL-versus-TOPICAL cohort (559 oral; 56,947 topical), 23 Core-list PTs and 31 Expanded-list PTs met the signal definition. Strongest primary signals included pericardial effusion (ROR 307; 95% CI 158-597), hypertensive crisis (ROR 1037; 95% CI 133-8117), pulmonary hypertension (ROR 932; 95% CI 118-7368), and pulmonary edema (ROR 1965; 95% CI 114-33,813). In an alopecia-restricted sensitivity cohort excluding hypertension/blood-pressure indications (146 oral; 24,367 topical), hemodynamic and effusion-related PTs (e.g., tachycardia, palpitations, orthostatic hypotension, syncope, and pericardial effusion) remained disproportionately reported, although event counts were smaller and confidence intervals were wider. Oral minoxidil PS/SS reports in FAERS showed disproportionate reporting of several cardiovascular PTs relative to topical minoxidil reports. However, because FAERS is a spontaneous reporting system without exposed-patient denominators and with important limitations including under-reporting, stimulated reporting, incomplete clinical information, and residual confounding, these findings should be interpreted strictly as hypothesis-generating reporting signals rather than evidence of incidence, relative risk, or definitive comparative clinical safety.